Neutrophil-lymphocyte index, a predictive marker for the diagnosis of complicated acute appendicitis

Abstract

Objective: To determine the diagnostic capacity of the neutrophil-lymphocyte index (NLR) to establish the diagnosis of complicated acute appendicitis in a national Peruvian hospital. Material and Method: Observational, descriptive, cross-sectional, retrospective study, diagnostic test type. The sample size was 333 patients with a diagnosis of acute appendicitis, being 207 patients with complicated acute appendicitis and 126 patients with uncomplicated acute appendicitis. A binary logistic regression model was used to generate a COR curve and estimate the operating characteristics of the Lymphocyte Neutrophil Index for complicated acute appendicitis, as well as the post-test probability for positive and negative cases. Results: The INL COR curve presented an AUC of 64.4% (95% CI 58.3%-70.5%) with a P-value < 0.05. The sensitivity and specificity for the diagnosis of complicated acute appendicitis were 69.08%, 61.11%, respectively, in turn, the post-test probability for positive and negative cases was 63% (58-68%) and 33% (27%)-39%) respectively. Conclusion: The INL has adequate precision for the diagnosis of complicated acute appendicitis, as well as significant variations in the post-test probability when the cases are positive or negative.